tun: windows: implement ring buffers
Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman
Jason A. Donenfeld
parent
a961aacc9f
commit
2e24e7dcae
@ -8,9 +8,9 @@ package tun
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"os"
|
||||
"sync"
|
||||
"sync/atomic"
|
||||
"time"
|
||||
"unsafe"
|
||||
|
||||
@ -20,39 +20,54 @@ import (
|
||||
)
|
||||
|
||||
const (
|
||||
packetExchangeAlignment uint32 = 4 // Number of bytes packets are aligned to in exchange buffers
|
||||
packetSizeMax uint32 = 0xf000 - packetExchangeAlignment // Maximum packet size
|
||||
packetExchangeSize uint32 = 0x100000 // Exchange buffer size (defaults to 1MiB)
|
||||
packetAlignment uint32 = 4 // Number of bytes packets are aligned to in rings
|
||||
packetSizeMax uint32 = 0xffff // Maximum packet size
|
||||
packetCapacity uint32 = 0x100000 // Ring capacity (defaults to 1MiB, must be a power of 2)
|
||||
packetTrailingSize uint32 = uint32(unsafe.Sizeof(packetHeader{})) + ((packetSizeMax + (packetAlignment - 1)) &^ (packetAlignment - 1)) - packetAlignment
|
||||
|
||||
ioctlRegisterRings uint32 = (0x22 /*FILE_DEVICE_UNKNOWN*/ << 16) | (0x800 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
|
||||
|
||||
retryRate = 4 // Number of retries per second to reopen device pipe
|
||||
retryTimeout = 30 // Number of seconds to tolerate adapter unavailable
|
||||
)
|
||||
|
||||
type exchgBufRead struct {
|
||||
data [packetExchangeSize]byte
|
||||
offset uint32
|
||||
avail uint32
|
||||
type packetHeader struct {
|
||||
size uint32
|
||||
}
|
||||
|
||||
type exchgBufWrite struct {
|
||||
data [packetExchangeSize]byte
|
||||
offset uint32
|
||||
type packet struct {
|
||||
packetHeader
|
||||
data [packetSizeMax]byte
|
||||
}
|
||||
|
||||
type ring struct {
|
||||
head uint32
|
||||
tail uint32
|
||||
alertable int32
|
||||
data [packetCapacity + packetTrailingSize]byte
|
||||
}
|
||||
|
||||
type ringDescriptor struct {
|
||||
send, receive struct {
|
||||
size uint32
|
||||
ring *ring
|
||||
tailMoved windows.Handle
|
||||
}
|
||||
}
|
||||
|
||||
type NativeTun struct {
|
||||
wt *wintun.Wintun
|
||||
tunFileRead *os.File
|
||||
tunFileWrite *os.File
|
||||
tunDev windows.Handle
|
||||
tunLock sync.Mutex
|
||||
close bool
|
||||
rdBuff *exchgBufRead
|
||||
wrBuff *exchgBufWrite
|
||||
rings ringDescriptor
|
||||
events chan Event
|
||||
errors chan error
|
||||
forcedMTU int
|
||||
}
|
||||
|
||||
func packetAlign(size uint32) uint32 {
|
||||
return (size + (packetExchangeAlignment - 1)) &^ (packetExchangeAlignment - 1)
|
||||
return (size + (packetAlignment - 1)) &^ (packetAlignment - 1)
|
||||
}
|
||||
|
||||
var shouldRetryOpen = windows.RtlGetVersion().MajorVersion < 10
|
||||
@ -102,14 +117,32 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
|
||||
return nil, fmt.Errorf("Unable to set name of Wintun interface: %v", err)
|
||||
}
|
||||
|
||||
return &NativeTun{
|
||||
tun := &NativeTun{
|
||||
wt: wt,
|
||||
rdBuff: &exchgBufRead{},
|
||||
wrBuff: &exchgBufWrite{},
|
||||
tunDev: windows.InvalidHandle,
|
||||
events: make(chan Event, 10),
|
||||
errors: make(chan error, 1),
|
||||
forcedMTU: 1500,
|
||||
}, nil
|
||||
}
|
||||
|
||||
tun.rings.send.size = uint32(unsafe.Sizeof(ring{}))
|
||||
tun.rings.send.ring = &ring{}
|
||||
tun.rings.send.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
|
||||
if err != nil {
|
||||
wt.DeleteInterface()
|
||||
return nil, fmt.Errorf("Error creating event: %v", err)
|
||||
}
|
||||
|
||||
tun.rings.receive.size = uint32(unsafe.Sizeof(ring{}))
|
||||
tun.rings.receive.ring = &ring{}
|
||||
tun.rings.receive.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
|
||||
if err != nil {
|
||||
windows.CloseHandle(tun.rings.send.tailMoved)
|
||||
wt.DeleteInterface()
|
||||
return nil, fmt.Errorf("Error creating event: %v", err)
|
||||
}
|
||||
|
||||
return tun, nil
|
||||
}
|
||||
|
||||
func (tun *NativeTun) openTUN() error {
|
||||
@ -119,9 +152,12 @@ func (tun *NativeTun) openTUN() error {
|
||||
}
|
||||
|
||||
var err error
|
||||
name := tun.wt.DataFileName()
|
||||
for tun.tunFileRead == nil {
|
||||
tun.tunFileRead, err = os.OpenFile(name, os.O_RDONLY, 0)
|
||||
name, err := windows.UTF16PtrFromString(tun.wt.DataFileName())
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
for tun.tunDev == windows.InvalidHandle {
|
||||
tun.tunDev, err = windows.CreateFile(name, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, 0, 0)
|
||||
if err != nil {
|
||||
if retries > 0 && !tun.close {
|
||||
time.Sleep(time.Second / retryRate)
|
||||
@ -130,72 +166,51 @@ func (tun *NativeTun) openTUN() error {
|
||||
}
|
||||
return err
|
||||
}
|
||||
}
|
||||
for tun.tunFileWrite == nil {
|
||||
tun.tunFileWrite, err = os.OpenFile(name, os.O_WRONLY, 0)
|
||||
|
||||
atomic.StoreUint32(&tun.rings.send.ring.head, 0)
|
||||
atomic.StoreUint32(&tun.rings.send.ring.tail, 0)
|
||||
atomic.StoreInt32(&tun.rings.send.ring.alertable, 0)
|
||||
atomic.StoreUint32(&tun.rings.receive.ring.head, 0)
|
||||
atomic.StoreUint32(&tun.rings.receive.ring.tail, 0)
|
||||
atomic.StoreInt32(&tun.rings.receive.ring.alertable, 0)
|
||||
|
||||
var bytesReturned uint32
|
||||
err = windows.DeviceIoControl(tun.tunDev, ioctlRegisterRings, (*byte)(unsafe.Pointer(&tun.rings)), uint32(unsafe.Sizeof(tun.rings)), nil, 0, &bytesReturned, nil)
|
||||
if err != nil {
|
||||
if retries > 0 && !tun.close {
|
||||
time.Sleep(time.Second / retryRate)
|
||||
retries--
|
||||
continue
|
||||
}
|
||||
return err
|
||||
return fmt.Errorf("Error registering rings: %v", err)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (tun *NativeTun) closeTUN() (err error) {
|
||||
for tun.tunFileRead != nil {
|
||||
for tun.tunDev != windows.InvalidHandle {
|
||||
tun.tunLock.Lock()
|
||||
if tun.tunFileRead == nil {
|
||||
if tun.tunDev == windows.InvalidHandle {
|
||||
tun.tunLock.Unlock()
|
||||
break
|
||||
}
|
||||
t := tun.tunFileRead
|
||||
tun.tunFileRead = nil
|
||||
windows.CancelIoEx(windows.Handle(t.Fd()), nil)
|
||||
err = t.Close()
|
||||
t := tun.tunDev
|
||||
tun.tunDev = windows.InvalidHandle
|
||||
err = windows.CloseHandle(t)
|
||||
tun.tunLock.Unlock()
|
||||
break
|
||||
}
|
||||
for tun.tunFileWrite != nil {
|
||||
tun.tunLock.Lock()
|
||||
if tun.tunFileWrite == nil {
|
||||
tun.tunLock.Unlock()
|
||||
break
|
||||
}
|
||||
t := tun.tunFileWrite
|
||||
tun.tunFileWrite = nil
|
||||
windows.CancelIoEx(windows.Handle(t.Fd()), nil)
|
||||
err2 := t.Close()
|
||||
tun.tunLock.Unlock()
|
||||
if err == nil {
|
||||
err = err2
|
||||
}
|
||||
break
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
func (tun *NativeTun) getTUN() (read *os.File, write *os.File, err error) {
|
||||
read, write = tun.tunFileRead, tun.tunFileWrite
|
||||
if read == nil || write == nil {
|
||||
read, write = nil, nil
|
||||
func (tun *NativeTun) getTUN() (handle windows.Handle, err error) {
|
||||
handle = tun.tunDev
|
||||
if handle == windows.InvalidHandle {
|
||||
tun.tunLock.Lock()
|
||||
if tun.tunFileRead != nil && tun.tunFileWrite != nil {
|
||||
read, write = tun.tunFileRead, tun.tunFileWrite
|
||||
tun.tunLock.Unlock()
|
||||
return
|
||||
}
|
||||
err = tun.closeTUN()
|
||||
if err != nil {
|
||||
if tun.tunDev != windows.InvalidHandle {
|
||||
handle = tun.tunDev
|
||||
tun.tunLock.Unlock()
|
||||
return
|
||||
}
|
||||
err = tun.openTUN()
|
||||
if err == nil {
|
||||
read, write = tun.tunFileRead, tun.tunFileWrite
|
||||
handle = tun.tunDev
|
||||
}
|
||||
tun.tunLock.Unlock()
|
||||
return
|
||||
@ -217,18 +232,30 @@ func (tun *NativeTun) Events() chan Event {
|
||||
|
||||
func (tun *NativeTun) Close() error {
|
||||
tun.close = true
|
||||
err1 := tun.closeTUN()
|
||||
windows.SetEvent(tun.rings.send.tailMoved) // wake the reader if it's sleeping
|
||||
var err, err2 error
|
||||
err = tun.closeTUN()
|
||||
|
||||
if tun.events != nil {
|
||||
close(tun.events)
|
||||
}
|
||||
|
||||
_, err2 := tun.wt.DeleteInterface()
|
||||
if err1 == nil {
|
||||
err1 = err2
|
||||
err2 = windows.CloseHandle(tun.rings.receive.tailMoved)
|
||||
if err == nil {
|
||||
err = err2
|
||||
}
|
||||
|
||||
return err1
|
||||
err2 = windows.CloseHandle(tun.rings.send.tailMoved)
|
||||
if err == nil {
|
||||
err = err2
|
||||
}
|
||||
|
||||
_, err2 = tun.wt.DeleteInterface()
|
||||
if err == nil {
|
||||
err = err2
|
||||
}
|
||||
|
||||
return err
|
||||
}
|
||||
|
||||
func (tun *NativeTun) MTU() (int, error) {
|
||||
@ -240,6 +267,8 @@ func (tun *NativeTun) ForceMTU(mtu int) {
|
||||
tun.forcedMTU = mtu
|
||||
}
|
||||
|
||||
// Note: Read() and Write() assume the caller comes only from a single thread; there's no locking.
|
||||
|
||||
func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
|
||||
select {
|
||||
case err := <-tun.errors:
|
||||
@ -248,142 +277,111 @@ func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
|
||||
}
|
||||
|
||||
retries := maybeRetry(1000)
|
||||
for {
|
||||
if tun.rdBuff.offset+packetExchangeAlignment <= tun.rdBuff.avail {
|
||||
// Get packet from the exchange buffer.
|
||||
packet := tun.rdBuff.data[tun.rdBuff.offset:]
|
||||
size := *(*uint32)(unsafe.Pointer(&packet[0]))
|
||||
pSize := packetAlign(size) + packetExchangeAlignment
|
||||
if packetSizeMax < size || tun.rdBuff.avail < tun.rdBuff.offset+pSize {
|
||||
// Invalid packet size.
|
||||
tun.rdBuff.avail = 0
|
||||
continue
|
||||
}
|
||||
packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
|
||||
|
||||
// Copy data.
|
||||
copy(buff[offset:], packet)
|
||||
tun.rdBuff.offset += pSize
|
||||
return int(size), nil
|
||||
}
|
||||
|
||||
// Get TUN data pipe.
|
||||
file, _, err := tun.getTUN()
|
||||
for !tun.close {
|
||||
_, err := tun.getTUN()
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
n, err := file.Read(tun.rdBuff.data[:])
|
||||
if err != nil {
|
||||
tun.rdBuff.offset = 0
|
||||
tun.rdBuff.avail = 0
|
||||
pe, ok := err.(*os.PathError)
|
||||
if tun.close {
|
||||
buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
|
||||
if buffHead >= packetCapacity {
|
||||
return 0, errors.New("send ring head out of bounds")
|
||||
}
|
||||
|
||||
buffTail := atomic.LoadUint32(&tun.rings.send.ring.tail)
|
||||
if buffHead == buffTail {
|
||||
windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
|
||||
continue
|
||||
}
|
||||
if buffTail >= packetCapacity {
|
||||
if retries > 0 {
|
||||
tun.closeTUN()
|
||||
time.Sleep(time.Millisecond * 2)
|
||||
retries--
|
||||
continue
|
||||
}
|
||||
return 0, errors.New("send ring tail out of bounds")
|
||||
}
|
||||
retries = maybeRetry(1000)
|
||||
|
||||
buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
|
||||
if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
|
||||
return 0, errors.New("incomplete packet header in send ring")
|
||||
}
|
||||
|
||||
packet := (*packet)(unsafe.Pointer(&tun.rings.send.ring.data[buffHead]))
|
||||
if packet.size > packetSizeMax {
|
||||
return 0, errors.New("packet too big in send ring")
|
||||
}
|
||||
|
||||
alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packet.size)
|
||||
if alignedPacketSize > buffContent {
|
||||
return 0, errors.New("incomplete packet in send ring")
|
||||
}
|
||||
|
||||
copy(buff[offset:], packet.data[:packet.size])
|
||||
buffHead = tun.rings.send.ring.wrap(buffHead + alignedPacketSize)
|
||||
atomic.StoreUint32(&tun.rings.send.ring.head, buffHead)
|
||||
return int(packet.size), nil
|
||||
}
|
||||
|
||||
return 0, os.ErrClosed
|
||||
}
|
||||
if retries > 0 && ok && (pe.Err == windows.ERROR_HANDLE_EOF || pe.Err == windows.ERROR_OPERATION_ABORTED) {
|
||||
retries--
|
||||
tun.closeTUN()
|
||||
time.Sleep(time.Millisecond * 2)
|
||||
continue
|
||||
}
|
||||
return 0, err
|
||||
}
|
||||
if n == 0 {
|
||||
if retries == 0 {
|
||||
return 0, io.ErrShortBuffer
|
||||
}
|
||||
retries--
|
||||
continue
|
||||
}
|
||||
tun.rdBuff.offset = 0
|
||||
tun.rdBuff.avail = uint32(n)
|
||||
}
|
||||
}
|
||||
|
||||
// Note: flush() and putTunPacket() assume the caller comes only from a single thread; there's no locking.
|
||||
|
||||
func (tun *NativeTun) Flush() error {
|
||||
if tun.wrBuff.offset == 0 {
|
||||
return nil
|
||||
}
|
||||
defer func() {
|
||||
tun.wrBuff.offset = 0
|
||||
}()
|
||||
retries := maybeRetry(1000)
|
||||
|
||||
for {
|
||||
// Get TUN data pipe.
|
||||
_, file, err := tun.getTUN()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
for {
|
||||
_, err = file.Write(tun.wrBuff.data[:tun.wrBuff.offset])
|
||||
if err != nil {
|
||||
pe, ok := err.(*os.PathError)
|
||||
if tun.close {
|
||||
return os.ErrClosed
|
||||
}
|
||||
if retries > 0 && ok && pe.Err == windows.ERROR_OPERATION_ABORTED { // Adapter is paused or in low-power state.
|
||||
retries--
|
||||
time.Sleep(time.Millisecond * 2)
|
||||
continue
|
||||
}
|
||||
if retries > 0 && ok && pe.Err == windows.ERROR_HANDLE_EOF { // Adapter is going down.
|
||||
retries--
|
||||
tun.closeTUN()
|
||||
time.Sleep(time.Millisecond * 2)
|
||||
break
|
||||
}
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (tun *NativeTun) putTunPacket(buff []byte) error {
|
||||
size := uint32(len(buff))
|
||||
if size == 0 {
|
||||
return errors.New("Empty packet")
|
||||
}
|
||||
if size > packetSizeMax {
|
||||
return errors.New("Packet too big")
|
||||
}
|
||||
pSize := packetAlign(size) + packetExchangeAlignment
|
||||
|
||||
if tun.wrBuff.offset+pSize >= packetExchangeSize {
|
||||
// Exchange buffer is full -> flush first.
|
||||
err := tun.Flush()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
// Write packet to the exchange buffer.
|
||||
packet := tun.wrBuff.data[tun.wrBuff.offset : tun.wrBuff.offset+pSize]
|
||||
*(*uint32)(unsafe.Pointer(&packet[0])) = size
|
||||
packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
|
||||
copy(packet, buff)
|
||||
|
||||
tun.wrBuff.offset += pSize
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
|
||||
err := tun.putTunPacket(buff[offset:])
|
||||
retries := maybeRetry(1000)
|
||||
for {
|
||||
_, err := tun.getTUN()
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
return len(buff) - offset, nil
|
||||
|
||||
packetSize := uint32(len(buff) - offset)
|
||||
alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packetSize)
|
||||
|
||||
buffHead := atomic.LoadUint32(&tun.rings.receive.ring.head)
|
||||
if buffHead >= packetCapacity {
|
||||
if retries > 0 {
|
||||
tun.closeTUN()
|
||||
time.Sleep(time.Millisecond * 2)
|
||||
retries--
|
||||
continue
|
||||
}
|
||||
return 0, errors.New("receive ring head out of bounds")
|
||||
}
|
||||
retries = maybeRetry(1000)
|
||||
|
||||
buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
|
||||
if buffTail >= packetCapacity {
|
||||
return 0, errors.New("receive ring tail out of bounds")
|
||||
}
|
||||
|
||||
buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
|
||||
if alignedPacketSize > buffSpace {
|
||||
return 0, errors.New("receive ring full")
|
||||
}
|
||||
|
||||
packet := (*packet)(unsafe.Pointer(&tun.rings.receive.ring.data[buffTail]))
|
||||
packet.size = packetSize
|
||||
copy(packet.data[:packetSize], buff[offset:])
|
||||
atomic.StoreUint32(&tun.rings.receive.ring.tail, tun.rings.receive.ring.wrap(buffTail+alignedPacketSize))
|
||||
if atomic.LoadInt32(&tun.rings.receive.ring.alertable) != 0 {
|
||||
windows.SetEvent(tun.rings.receive.tailMoved)
|
||||
}
|
||||
return int(packetSize), nil
|
||||
}
|
||||
}
|
||||
|
||||
//
|
||||
// LUID returns Windows adapter instance ID.
|
||||
//
|
||||
func (tun *NativeTun) LUID() uint64 {
|
||||
return tun.wt.LUID()
|
||||
}
|
||||
|
||||
// wrap returns value modulo ring capacity
|
||||
func (rb *ring) wrap(value uint32) uint32 {
|
||||
return value & (packetCapacity - 1)
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user